Method for producing a pellicle for lithography

ABSTRACT

There is provided a pellicle for lithography which has at least, a pellicle film for dustproof protection, a pellicle frame to which the pellicle film is adhered, an adhesive layer provided on one end face of the pellicle frame in order to adhere the pellicle film, and a sticking layer formed on another end face of the pellicle frame, wherein the pellicle film is formed by a die coating machine and a method for producing it. There can be provided a relatively large-sized pellicle for lithography which has a pellicle film with little unevenness of film thickness and with a uniform and high light transmission can be produced easily and at low cost, compared with those using the conventional spin coater.

This is a Division of Application Ser. No. 10/695,871 filed Oct. 30,2003. The entire disclosure of the prior application is herebyincorporated by reference herein in its entirety.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to a pellicle for lithography used fordustproof protection of a mask for lithography used in lithography forforming a fine pattern, and a method for producing it, especially to alarge-sized pellicle for lithography used when a liquid-crystal displaypanel is manufactured.

2. Description of the Related Art

A pattern is formed by exposing a semiconductor wafer or a liquidcrystal substrate with light in manufacture of semiconductor such asLSI, VLSI, or the like, or manufacture of a liquid-crystal displaypanel. In this case, if dust has adhered to an exposure original plate(a mask for lithography) to be used, the dust absorbs light or bendslight. Thus, an transferred pattern may be deformed, or an edge may berough, and also the ground may be soiled to be black, resulting indegradation of a dimension, a quality, and an appearance or the like,which may lead to a problem of a lowering of performance or productionyield of a semiconductor device, a liquid-crystal-display panel, or thelike.

For this reason, these works are usually done in a clean room. However,since it is difficult to always keep an exposure original plate cleaneven in the clean room, there is adopted a method of attaching apellicle for dustproof protection which transmits the light for exposureto the surface of the exposure original plate. In this case, dust doesnot adhere directly to the surface of the exposure original plate butadheres to the pellicle film. Accordingly, if the focus is on thepattern of the exposure original plate at the time of lithography, thedust on the pellicle film does not affect the transfer.

Such a pellicle fundamentally consist of a pellicle film produced byapplying an application liquid which consists of a cellulose nitrate, acellulose acetate or the like, through which light used for the exposureis transmitted well, to a smooth substrate by a spin coat method, dryingthe solvent in this application liquid, and peeling a transparent filmformed on the substrate from the substrate, and a pellicle frame made ofaluminium alloys, such as A7075 subjected to black alumite treatment,stainless steel, polyethylene, or the like, which are adhered byapplying a good solvent for the pellicle film to one end face of theframe, and then air-drying it to adhere them (for example, see JapanesePatent Application Laid-open (kokai) No. 58-219023), or being adheredwith adhesives, such as an acrylate resin, an epoxy resin or the like(for example, see U.S. Pat. No. 4,861,402 specification or JapanesePatent publication (kokoku) No. 63-27707). Furthermore, the pellicle hasa sticking layer for attaching the pellicle to an exposure originalplate, made of a polybutene resin, a polyvinyl acetate resin, anacrylate resin, or the like and formed on another end face of thepellicle frame, and a reticle sticking layer protection liner forprotecting the reticle sticking layer.

In recent years, a pellicle has come to be used also in a lithographyprocess in processes for production of a liquid-crystal display panel orthe like. In this case, as a pellicle to be used, a pellicle with a verylarge size as 1000 cm² or more is needed in the case of a one-timeexposure formula according to a mirror projection method or the like, ascompared with those used in the semiconductor production process (750cm² or less, one having a diameter of 12 inch at the largest ispractically used). The spin coat method had been conventionally used asa production method of the pellicle film also in the case of a pelliclewith such a large size.

However, when the spin coat method is used as a method for producing apellicle film with a large size as, for example, 1000 cm² or more, therewere the following problems: 1) It is necessary to use a quite largeamount of application liquid to be applied on the substrate. Almost allthe application liquid is shaken off during rotation, and does notremain as an application liquid film. Therefore, it is quite wasteful,and a manufacturing cost is increased; 2) When the film is formed on alarge-sized substrate by the spin coat method, unevenness of a filmthickness is increased (for example, a film thickness distribution inplane is over ±10%), and a light transmission is lowered. Therefore, thepellicle film with a sufficient performance cannot be obtained; 3) It isdifficult to rotate a large substrate, and it is a problem to rotate thelarge and heavy substrate at high rate. Therefore the manufacturing costbecomes high. Especially important problems are the problems 1) and 2).When the pellicle film having a large size is actually produced by aspin coat method, there has been a problem that optical characteristicswhich the pellicle film should have essentially can be hardly obtained.

SUMMARY OF THE INVENTION

The present invention has been accomplished to solve the above-mentionedprevious problems. An object of the present invention is to provide apellicle for lithography with a comparatively large size which can beproduced easily and surely, with a low cost compared with a conventionalspin coat method, and has a pellicle film having little unevenness of afilm thickness and uniform and high light transmission, and a method forproducing it.

To achieve the above mentioned object, the present invention provides apellicle for lithography which has at least, a pellicle film fordustproof protection, a pellicle frame to which the pellicle film isadhered, an adhesive layer provided on one end face of the pellicleframe in order to adhere the pellicle film, and a sticking layer formedon another end face of the pellicle frame, wherein the pellicle film isformed by a die coating machine.

As described above, when the pellicle film is formed by a die coatingmachine, unevenness of a thickness of the film is suppressed, and alight transmission is also high compared with the pellicle film formedby the conventional spin coat method or the like, even in the case thatit is a pellicle film for a large-sized pellicle used for a lithographyprocess in which a larger-sized substrate is dealt with compared withthose used for the conventional semiconductor production process or thelike. As a result, if such a pellicle is used in a lithography process,a pattern can be suitably formed on a large-sized substrate for patternformation.

In this case, the pellicle for lithography wherein an area of thepellicle film is 1000 cm² or more, and a distribution of a thickness ofthe film in plane is within ±10% is provided.

As described above, according to the pellicle film of the pellicle forlithography of the present invention, even if an area is 1000 cm² ormore, a distribution of a thickness of the film in plane is within ±10%.Accordingly, it has very little unevenness of a film thickness, ascompared with the conventional one having a film thickness distributionlarger than 10%, and also has a high light transmission, and is suitableto be used for a large-scale lithography process.

In this case, the above-mentioned pellicle for lithography is used inthe lithography process for manufacture of liquid-crystal-display panel.

The pellicle film of the pellicle for lithography of the presentinvention has very little unevenness of a film thickness and a uniformlight transmission thereof in a plane, even if it is large-sized as anarea of 1000 cm² or more. Accordingly, it is especially preferable to beused in a lithography process for manufacture of a liquid-crystaldisplay panel by which a comparatively large-sized substrate for patternformation will be treated.

Moreover, the present invention relates to a method for producing apellicle film comprising at least a process of dissolving a raw materialof the pellicle film in a solvent to prepare an application liquid, aprocess of coating a substrate with the application liquid, and aprocess of drying the substrate to which the application liquid isapplied wherein the coating process is carried out with a die coatingmachine.

As described above, according to the present invention, in production ofthe pellicle film, the coating process of the application liquid whichhas been conventionally carried out with a spin coater or the like iscarried out with a die coating machine. Accordingly, even when thepellicle film with a comparatively large area is produced, the waste ofthe application liquid is little. Furthermore, the pellicle film can beproduced easily and at low cost, because it is not necessary to rotate asubstrate during application. Moreover, there is produced a pelliclefilm having very little unevenness of a thickness of the film and a highand uniform light transmission.

In this case, it is desirable to perform the above-mentioned coatingprocess with the die coating machine in an amount of an applicationliquid in the range obtained from the following formula (1).0.9×V1<V<1.1×V1  (1)(V1=S×t/(D/100))

-   V(m³): an amount of an application liquid-   S (m²): an area of a substrate-   t(m): a film thickness after drying-   D (%): a concentration of application liquid

As described above, the film thickness distribution after drying can bemade in the small range as ±10% or less of the desired film thicknessafter drying by setting an amount of an application liquid V into theamount of the range larger than 0.9 times V1 and smaller than 1.1 timesV1 which is a desired amount of an application liquid calculatedbackward from the desired film thickness after drying t, the substratearea S, and a concentration of an application liquid D.

In this case, the above-mentioned drying process desirably comprisesair-dry for 5 minutes or more in the air of which a flow rate on thesurface of the substrate is 30 cm or less per second followed by dryingat a temperature more than the boiling point of the application liquid.

As described above, if the drying process comprises air-dry for 5minutes or more in the air of which a flow rate on the surface of thesubstrate is 30 cm or less per second followed by drying at atemperature more than the boiling point of the application liquid,generation of film thickness unevenness of the pellicle film due to thedrying process can be suppressed.

As described above, according to the present invention, the pelliclefilm having an area of 1000 cm² or more is produced.

As described above, according to a method for producing a pellicle filmof the present invention, even when the large one wherein the area ofthe pellicle film is 1000 cm² or more is produced, only a little amountof the application liquid is required, as compared with the conventionalspin coat method, and it is not necessary to rotate a substrate duringapplication. Thus, the pellicle film can be produced easily and at lowcost and moreover, there can be produced a pellicle film having verylittle unevenness of a film thickness and has a high and uniform lighttransmission.

Moreover, according to the present invention, there is provided a methodfor producing a pellicle for lithography comprising at least providingan adhesive layer on one end face of a pellicle frame, adhering thepellicle film produced by the above-mentioned method of the presentinvention with the adhesive layer to one end face of the above-mentionedpellicle frame, and the pellicle for lithography produced by thismethod.

The pellicle for lithography produced described above has a suppressedunevenness of a film thickness and a uniform light transmission, ascompared with the pellicle film formed by the conventional spin coatmethod or the like, even in the case of producing a comparativelylarge-sized one used in the lithography process for, for example,manufacture of liquid-crystal display panel. Therefore, if such apellicle is used at a lithography process, a pattern can be formedsuitably on a large-sized substrate for pattern formation.

As explained above, according to the present invention, the pelliclewhich has little local unevenness of film thickness and little deviationthereof in plane, and has a uniform and high light transmission can beproduced easily and at low cost, using the die coating machine, comparedwith those using the conventional spin coater, in performing filmformation of the pellicle film of the pellicle with very large sizecompared with those used in the semiconductor production process or thelike.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing constitution of the pellicle of thepresent invention.

FIG. 2 is a schematic view showing one example of a die coating machineused for the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

As a result of further studying, the inventors of the present inventionhave found that a pellicle for lithography which has a pellicle filmhaving very little unevenness of a film thickness and has a high anduniform light transmission can be produced easily and at low cost, ifthe pellicle film is formed by a die coating machine instead of a spincoater as performed conventionally, when producing a relatively largepellicle for lithography as used in a lithography process formanufacture of liquid-crystal display panel. Thereby, the presentinvention has been completed.

The present invention will be explained below in detail, but the presentinvention is not limited thereto.

As shown in FIG. 1, a pellicle 5 of the present invention consists of,at least, a pellicle frame 1, a pellicle film 2, a sticking layer 3, andan adhesive layer 6. The pellicle 5 is what the pellicle film 2 isadhered with the adhesive layer 6 for adhesion of the pellicle film toone end face of the pellicle frame 1. In that case, the sticking layer 3for adhesion of a reticle is usually formed in another end face, and aliner for protection (a release layer) 4 is attached, in a manner thatit can be peeled off, to the lower end face of the sticking layer 3 foradhesion of the reticle.

The pellicle film of the pellicle for lithography of the presentinvention has little unevenness of a film thickness and has a uniformlight transmission, even if it is a large-sized, compared with thosehaving an area size of 750 cm² or less used for a conventionalmanufacturing process of a semiconductor or the like, for example, thoseused at a lithography process in manufacture of a liquid-crystal displaypanel or the like. That is, even if the pellicle film is a large-sizedone which has an area of 1000 cm² or more, it has very little unevennessof a thickness as being within ±10% and further within ±5%, and has auniform and high light transmission, as compared with those having alarger thickness distribution as being larger than ±10% in a planeformed by the conventional spin coat method or the like. Moreover, anarea of the pellicle film can be 10000 cm² or more, and those in therange of 50000 cm² or more is also possible. Even if it is such alarge-sized one, it has little unevenness of a thickness and a highlight transmission. A thickness of the pellicle film described above isdesirably in the range of 0.5 μm or more and 20 μm or less from thepoints of a film strength, cost performance and the like.

Such a pellicle film should be produced by, at least, a process ofdissolving a raw material of the pellicle film in a solvent to preparean application liquid, a process of coating a substrate with theapplication liquid by a die coating machine, and a process of drying thesubstrate to which the application liquid is applied.

First, the process of preparing an application liquid will be explained.Although the kind of a raw material of the pellicle film is notparticularly limitative, there may be used for example, cellulosenitrate, cellulose acetate, amorphous fluorine polymer, or the like.Examples of amorphous fluorine polymer may include: Cytop (manufacturedby Asahi Glass Co., Ltd., tradename), Teflon AF (manufactured by Dupont,tradename), or the like. These polymers (the raw material of thepellicle film) may have been dissolved in the solvent beforehand, or itmay be dissolved in a solvent if needed, when the pellicle film isproduced, and used. For example, it may be suitably dissolved in afluorine solvent or the like.

The coating process may be performed by a die coating machine. Althoughthe kind of a die coating machine is not particularly limitative, it ispreferable to use those wherein a uniformity of a thickness of anapplication liquid film is high, when application liquid is applied, andunevenness of the film thickness of the pellicle film after drying ishardly caused.

For example, the die coating machine 11 as shown in FIG. 2 can be used.The die coating machine 11 is connected to a tank 13 which contains theapplication liquid through the discharge pump 12. The application liquidof the tank 13 is discharged with the discharge pump 12, while the diecoating machine 11 moves, and thereby the substrate 15 placed on thetable 14 is coated with the application liquid in a desired thickness.

In the pellicle film with which optical uniformity is especiallyrequired, since the uniformity of the film after application isimportant, it is necessary that a slot die of the die coating machinefaces downward, and the discharged liquid is appied on the flatsubstrate which is placed on the horizontal plane. As the die coatingmachine, there can be used a well-known conventional technique. Forexample, those exemplified in Japanese Patent publication No. 2644457and Japanese Patent Application Laid-open (kokai) No. 10-421 can besuitably used as such a die coating machine. For example, there can beused the slot die coating machine FLORIA II (manufactured by Chugai RoCo., Ltd., tradename), a super precision discharge type FAS coatingequipment MH-1600 (manufactured by SHIMADZU CORPORATION, tradename) orthe like.

An amount of an application liquid to be applied by the die coatingmachine can be suitably decided by the desired thickness after drying.

Specifically, the amount of an application liquid is preferably definedaccording to the following formula.0.9×V1<V<1.1×V1  (1)(V1=S×t/(D/100))

-   V(m³) : An amount of an application liquid-   S (m²) : An area of a substrate-   t(m): A film thickness after drying-   D (%): A concentration of an application liquid

The amount of the application liquid V can be obtained from V1 which isa desired amount of an application liquid calculated backward from thedesired film thickness after drying t, the substrate area S, and aconcentration of an application liquid D. The film thicknessdistribution after drying can be made in the small range, for example,as ±10% or less of the desired thickness after drying by setting anamount of an application liquid V into the amount of the range largerthan 0.9 times V1 and smaller than 1.1 times V1. Since the filmthickness after drying is defined by an amount of an application liquidat the time of coating, it is necessary that an amount of an applicationliquid at the time of coating is to be in the range of at least ±10% orless of a desired amount of an application liquid. If the coating isperformed by the die coating machine, it is easy to be coated with theapplication liquid in ±10% or less of range. As a result, the filmthickness after drying can be made within ±10%. Especially, it is alsopossible to make it within ±5%, if it is a die coating machine.

A drying process can be performed by air drying for volatilizing asolvent to some extent in the air first, and then drying by heating forremoving a solvent completely with a dryer or a hot plate. If theabove-mentioned air dry performed before the heating-dry is performedunder the strong descending air current in a clean room, unevenness of athickness will be caused to the finished film. Therefore, it isdesirable to dry for 5 minutes or more under a suitable air current,preferably under air current of 30 cm or less per second. In addition, atime of drying is desirably less than 100 minutes. Because, even ifdrying is performed longer than 100 minutes, effect of the drying doesnot improved so much, but a harmful effect such as adhesion of dust maybe increased. Moreover, it is desirable to perform the above-mentionedheating-dry by a dryer or the like with making a temperature differencebetween a substrate and a film surface of an application liquid film assmall as possible, in order to prevent a convection current fromoccurring in a film of an application liquid film during drying.

Next, the pellicle frame, the adhesive layer, and the sticking layerwhich constitute the pellicle for lithography will be explained. In thepresent invention, they can be made of known material.

The material of the pellicle frame is not particularly limitative.Examples thereof may include those obtained by anodizing the aluminummaterial used conventionally to conduct black oxide finish with a blackdye, steel, stainless steel, resins such as polyacetal, polycarbonate,PMMA (poly methyl methacrylate), and an acrylate resin, blue glass,quartz glass, and the like.

Although the surface of the pellicle frame is usually roughened bysandblasting or chemical polishing in the present invention, the methodof roughening the surface of the frame is not limitative. For example,when aluminum material is used, there is known a method of roughening asurface by performing a blast treatment of the surface with stainlesssteel, carborundum, glass beads, or the like, and then furtherperforming a chemical polishing with NaOH or the like, which can be usedfor the present invention.

On the other hand, if there is no limitation especially in a lithographyprocess, the surface of the pellicle frame can be remained smooth, anddyeing or painting may not be performed. So, it will not be restrictedto these.

Moreover, at least one gas-passage may be provided in at least one sidesurface of a pellicle frame. However, if there is no need, it is notnecessary to provide the gas-passage.

In the case that the gas-passage is provided, the size, the shape, thenumber, and the place of the gas-passage is not limitative. It isdesirable to select the size, the shape, the number, and the placedepending on the mesh size of the filter provided to the gas passageopening which is an opening of the gas-passage, a filtering-area or anamount of air flow resulted from them. It is preferable not to provide alarge gas-passage opening more than necessary, but to provide agas-passage opening with a minimum size to be required.

There is especially no limit in the size, the shape, and the material ofa filter for removal of dust used for the gas-passage opening, as far asit can be provided at the gas-passage opening. Examples of the materialof this filter may include a resin (PTFE (polytetrafluoro ethylene),nylon 66 or the like), metals (316L stainless steel or the like),ceramics (alumina, aluminum nitride, or the like), or the like.

The adhesive of the adhesive layer for adhesion of a pellicle film maybe one used conventionally. For example, a polyacrylate adhesive, anepoxy resin adhesive, silicone resin adhesives, and fluorine polymer,such as fluorine-containing silicone adhesives, or the like can bementioned. A silicone resin and fluorine polymer are suitableespecially.

The sticking layer for sticking of reticle can be formed by adouble-stick tape, a silicone resin binder, an acrylic binder, ahot-melt binder, or the like.

The pellicle of the present invention can be produced by adhering apellicle film with the adhesive layer for adhesion of a pellicle film toone end face of the pellicle frame by a usual method, and usuallyforming the sticking layer for attaching a reticle in another end face.A mold release layer (a liner for protection) is formed on the end faceon the side of the sticking layer for attaching a reticle in a way thatit can be peeled off. Here, the adhesive layer for adhesion of apellicle film formed on one end face of the pellicle frame can be formedby diluting adhesives with a solvent if necessary, applying it on oneend face of the pellicle frame, heating it to be dried and cured. Inthis case, as the method of application of adhesives, a brush coating,the method by a spray, an automatic dispenser, or the like can be used.

The material of the above-mentioned liner for protection of the stickinglayer for attaching a reticle is not limitative. Examples of them mayinclude PET (polyethylene terephthalate), PTFE, PFA, PE, PC(polycarbonate), vinyl chloride, PP (polypropylene), stainless steel,aluminum foil, or the like. Those obtained by applying the mold releaseagent which affording a releasable property from a sticking layer on theabove material can be used.

EXAMPLE

Hereafter, the present invention will be specifically explainedreferring to an example and a comparative example.

Example 1

First, the frame made of an aluminum alloy with an outer dimension of800 mm×900 mm×5 mm width and a frame thickness of 6 mm was prepared fora pellicle frame. The gas-passage with a diameter of 1.0 mm was preparedin the center of one side face of this frame.

The surface of the frame was cleaned, and then subjected to surfacetreatment using glass beads for one minute with a sandblasting apparatusat a discharge-pressure of 1.5 kg/cm², to roughen the surface.Subsequently, it was subjected to treatment in a NaOH processing bathfor 10 seconds and cleaned, and then was anodized and black-dyed, andsubjected to a sealing treatment, to form a black oxide coating on thesurface.

This frame made of an aluminum alloy was cleaned using pure water and anultrasonic cleaner together. Subsequently, a silicone binder was appliedusing a spray coating apparatus to the internal surface of this frame at1 μm.

Subsequently, a filter made of PTFE having a dust filtration size (meshsize) of 0.1 to 3.0 μm, a filtration efficiency of 99.9999%, and a widthof 9.5 mm, a height of 2.5 mm, a thickness of 300 μm was attached at theopening of the above-mentioned gas-passage. Thereby, the pellicle framewas produced.

Subsequently, Teflon AF1600 (manufactured by U.S. Dupont, tradename) wasdissolved in a fluorine solvent Fluorinert FC-75 (manufactured by U.S.3M, tradename), to prepare a solution with 6 % of concentration.

Then, a coated film with a film thickness of 35 μm was formed using aslot die coating machine (FROLIA II, manufactured by Chugai Ro Co., Ltd,tradename) with the solution (an application liquid concentration D=6%)on the surface of a synthetic quartz substrate with 1000 mm×1000 mm (asubstrate area S=1 m²) and a thickness of 5 mm, which was subjected tomirror polishing, in order to obtain a pellicle film with a thickness of2 μm (a thickness after drying t=2×10⁻⁶ m) (the amount of an applicationliquid V=the coating film thickness x the area of the substrate=35×10⁻⁶m³ (35 ml)) (V1=S×t/(D/100)=33.3×10⁻⁶ m³, therefore, 0.9×V1<V=35×10⁻⁶ m³(35 ml)<1.1×V1).

Then, this coated film was dried by standing for 30 minutes in thevertical laminar flow type clean booth with an air flow rate of 10 cm,and then dried for 2 minutes at 180° C. in the clean bake furnace.Thereby the pellicle film with a thickness of 2 μm was formed.

Then, the pellicle film and the jig for producing of a pellicle whichhas a frame with an outer size of 1000 mm×1000 mm×10 mm width and athickness of 10 mm were adhered together using the epoxy adhesiveAraldite Rapid (manufactured by Showa Highpolymer Co., Ltd., tradename),and then peeled off from the surface of the synthetic quartz substratein air.

Then, the silicone binder was applied to one end face of the pellicleframe made of an aluminum alloy prepared as mentioned above, heated at100 ° C. for 10 minutes to be dried and cured. Thereby, a sticking layerwas formed. Moreover, the fluorine polymer adhesives CT 69 (manufacturedby Asahi Glass Co., Ltd., tradename) diluted with a fluorine solvent CTsolve 180 (manufactured by Asahi Glass Co., Ltd., tradename) was appliedto another end face of the pellicle frame made of aluminium alloy, andheated at 100° C. for 10 minutes to be dried and cured. Thereby, theadhesive layer was formed. The liner made of PET was prepared andattached to the above-mentioned sticking layer of the pellicle framewith the liner attaching apparatus equipped with an image-processingpositioning device by the CCD camera.

After bringing the adhesive layer of the above-mentioned pellicle frameclosely contact with the surface of the pellicle film made of TeflonAF1600 prepared above, the pellicle frame was heated with IR lamp toweld the pellicle frame and the pellicle film together. Two of theframes of the pellicle frame and the jig for producing of the pelliclewere fixed with facing the adhesion side of the pellicle frame upwardand attaching it to the jig for fixing, so that the position of the jigfor fixing might not shift relatively. Subsequently, the frame of thejig for producing of the pellicle outside the pellicle frame was pulledup, and fixed, and then the tension of 0.5 g/cm was given to thepellicle film part outside the pellicle frame.

Subsequently, cutting removal of the unnecessary pellicle film outsidethe pellicle frame was carried out, using the cutter attached to theSCARA robot by moving the cutter along with the circumference section ofthe adhesive layer portion of the above-mentioned pellicle frame withdropping Fluorinert FC-75 (manufactured by Dupont, tradename) at 10μl/min by the tube type dispenser.

The distribution of the thickness of the pellicle film of the pelliclefor lithography produced described above was measured with thetransmission measurement apparatus manufactured by Otsuka ElectronicsCo., Ltd. The measurement was performed by measuring inside the filmsurface with 1000×1000 mm in the shape of a lattice at an interval of 50mm. The result of the measurement and the amount of the applicationliquid in the film formation test of this example were shown below inthe table 1.

Comparative Example 1

The thickness distribution was measured by the same method as Example 1as for the pellicle film of the pellicle for lithography which wasproduced by the same method as Example 1 except that the film formationof the pellicle film was carried out by a spin coat method. The resultof the measurement and an amount of the application liquid in a filmformation test of this comparative example were shown in Table 1.

TABLE 1 Amount of Film formation Distribution application method inplane liquid(ml) Example 1 Slot die coating  ±5% 35 machine ComparativeSpin coating ±11% 350 Example 1 machine

The table 1 shows that a thickness distribution of the pellicle film inplane was within ±5% in Example 1 wherein the film formation of thepellicle film was carried out by the die coating machine, and it isclear that a higher thickness uniformity is achieved, as compared with±11% in Comparative example 1 wherein the film formation was carried outby the spin coater. If the thickness uniformity is high as describedabove, the light transmission is uniform.

Moreover, the amount of the application liquid needed for performingfilm formation of the pellicle film in Example 1 was a tenth of theamount in Comparative Example 1. Accordingly, it was revealed that asignificant amount of the application liquid can be saved.

The present invention is not limited to the above-described embodiment.The above-described embodiment is a mere example, and those having thesubstantially same structure as that described in the appended claimsand providing the similar action and effects are included in the scopeof the present invention.

1. A method for producing a pellicle film comprising at least:dissolving a raw material of a pellicle film in a solvent to prepare anapplication liquid, coating a substrate with the application liquidusing a die coating machine and with an amount of an application liquidbeing in the range:0.9×V1<V<1.1×V1(V1=S×t/(D/100)) V (m³): an amount of an application liquid S (m²): anarea of a substrate t (m): a film thickness after drying D (%): aconcentration of application liquid, drying the substrate to which theapplication liquid is applied; to form the pellicle film with an area of1000 cm² or more and a film thickness distribution after drying of±10%or less, and adhering the pellicle film to a jig for producing apellicle.
 2. The method for producing a pellicle film according to claim1 wherein the drying comprises air-dry for 5 minutes or more in the airof which a flow rate on the surface of the substrate is 30 cm or lessper second followed by drying at a temperature more than a boiling pointof the application liquid.
 3. A method for producing a pellicle forlithography comprising at least providing an adhesive layer on one endface of a pellicle frame, and adhering with the adhesive layer thepellicle film and the jig for producing a pellicle produced by themethod according to claim 1 to the one end face of the pellicle frame.4. A method for producing a pellicle for lithography comprising at leastproviding an adhesive layer on one end face of a pellicle frame, andadhering with the adhesive layer the pellicle film and the jig forproducing a pellicle produced by the method according to claim 2 to theone end face of the pellicle frame.
 5. The pellicle for lithographyproduced by the method according to claim
 3. 6. The method for producinga pellicle film according to claim 1, wherein the substrate is notrotated during the coating process with the application liquid.